I am having trouble with Photoshop CS6-extended which I have only been using it for about 10 days. When I paint I start with a new layer that i locked but I click on new layer
then I go to color picker to choose a bluish purple. Then being on the same layer I choose a lighter color by going to color picker I want that lighter color to go on top of the bluish purple.

With that lighter color i want it to be like a highlight. Is it really necessary to have that highlight on a separate layer.

What if I have a bluish purple and i want to slightly change that color? Here is an example of what I am asking about. On this sample I wanted the lighter color on top.

What am I doing wrong?

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